1. Field of the Invention
The present invention relates to a ring oscillator and, more particularly, to a ring oscillator having a variable frequency.
2. Description of the Related Art
Ring oscillators are widely used in electronic equipment such as computers, televisions, videocassette recorders (VCRs) and the like. Typically, a ring oscillator comprises a series of discrete components including transistors, capacitors, etc. For a predetermined combination of discrete components, a conventional ring oscillator only produces a fixed frequency. That is, once assembled, the frequency of the oscillating signal generated by a ring oscillator cannot be externally adjusted. The result is that a conventional ring oscillator can only be used in a limited manner in electronic equipment.
Accordingly, a need remains for a ring oscillator having an externally adjustable variable frequency.